Hi,

I think I fried my external Toshiba Canvio USB 3.0 hard drive. Windows reported a power surge and after that the hard drive stopped. The status LED is off.

I disassembled the hard drive and connected it directly with the SATA power and data connector, but again, the hard drive doesn't spin at all. So I think the PCB is broken. Maybe it is just a TVS diode, but I have no clue, where on the PCB the TVS diodes might be.

Can someone else identify it/them?

Small image of PCB:
https://onedrive.live.com/?cid=2557377a176e415c&id=2557377A176E415C%21107&v=3&ithint=photo,.jpg&authkey=!AOjrYPDk9sbXyN0

Full size image of PCB:
https://ke30fw.bn1.livefilestore.com/y2mFXQ0RtyNXFG5kWZxDUZstR47t7Svok0WRtAGVJN57BEuW0XcnVbCnWVQ5DD0fDYaL9mS0-u47J7uVDB0-OgS73fKeTVyfSLEHaYGs0WTcpeGyJ5QoiE0RcTkyzRcROtl/20140223_231141.jpg?psid=1

Thanks in advance,
Tobias

There does not appear to be a TVS diode on your PCB.

There is a 2A fuse at the SATA power connector. Measure its resistance. Also measure the resistances of the zero ohm resistors.

Also measure the resistances between each of the Vcore and Vio test points and Ground. You could use the coils as your test points if they are more convenient, or measure the resistances of the associated capacitors.

If all is OK, then power up the board on its own and measure the Vcore and Vio voltages. The SDRAM is rated for 2.4V-2.7V, so I would think that Vio would be +2.5V.

W9464G6JH-5, Winbond, SDRAM, 4Mbitx16, 4 Banks, 2.4V-2.7V:
http://pdf.datasheetarchive.com/indexer ... 916738.pdf

_________________
A backup a day keeps DR away.

Many thanks for your help. I am very busy at work this week, so I might not be able to check the PCB before Friday. But thanks again. I don't know, if I would have been able to figure out, what is what and where to measure!
I will post the results.

Today I took out my multimeter and measured at the points you mentioned:

- The 2A fuse is blown.
- The resistance of the zero ohm resisters is 0.
- The resistance between Vcore and ground is 274 ohm.
- The resistance between Vio and ground is 12.08k ohm.

I think I will order a 2A fuse, but what kind? Do I need a slow- or fast-blow fuse?

Could I - just for testing - use a little wire instead of the fuse, to see, if everything else is ok or is that way too risky?

You can do that, but on your own risk...IF the board has more problems it can be fatal.

_________________
Rescue IT Datarecovery service Sweden
Rescue IT Dataräddning Göteborg AB
http://www.rescue-it.se

I would use a picofuse, or you could attach a regular 2A fast-blo fuse with wires.

Best of luck.

If you have any way to backup the contents of IC602 without risking damage to it, then that would be advisable.

_________________
A backup a day keeps DR away.

I replaced the fuse with a new one and measured Vcore and Vio. Both values are below 100mV.

I checked the capacitor on the right side of the fuse and it has a short. I removed the fuse again (thought I might have shortened it), but the capacitor is still shorted without visible solder joints.

Could the board be tested/used without the capacitor?
What could be the reason for the low voltage?

Remove the capacitor and check if it still shows the shorting or if the shorting is on the board.
if capacitor is faulty, replace it or you can even run w/o capacitor.
if there is a shorting you will any ways get near to zero Vcore and Vio.

It could be a mould defect, but there appears to be a "divot" in the TLS2505 motor controller chip at the lower RH corner of the package.

_________________
A backup a day keeps DR away.

Thanks, I'll try that. But what would be the correct value of that capacitor? I'm sure it's there for a reason. I was looking for a datasheet of the TLS2505 or an application note to determine that
value but I couldn't find any. Does anyone happen to know where to obtain that information?

And for the layman of foreign language: What is a mould defect or divot and what are the concequences?

I think you would need to contact Texas Instruments directly in order to obtain a datasheet, assuming they will release it to you at all (I can't find one in the usual places). As for the "divot", I'm referring to the small hole in the IC package. This could be a sign that the IC has failed and that the short circuit you are measuring is actually internal to the IC, not necessarily within the capacitor.

As for the reason behind the capacitor, it is there to filter noise on the +5V supply. If your PSU is clean, then you could probably run the drive without the capacitor.

If I were trying to narrow down the source of the short, I would remove the two zero-ohm resistors and measure the resistance between ground and the load side of each resistor. I could be wrong, but the following circuit is my best guess as to the path that the +5V supply takes after each of the resistors. By removing the resistors, you could determine which path is responsible for the short.

_________________
A backup a day keeps DR away.

Ideally Speaking why don't you look for donor PCB and Swap ROM IC602 and start the drive.
Much easier than diagnosing and trying to repair the same PCB

Good morning.
I have a similar problem with the same pcb . Bypassed the fuse, which was burned, disc started and then stop and start again .
The PC does not detect it . After a bit ' has stopped work.
I checked the capacitor under the fuse seemed fine but I 've lost it. How to replace it?
I note that the two ends of this capacitor measure continuity of 30 ohms ( referable to resistance betwenn 5v and zero point).
It's normal?
Thanks.

A resistance of 30 ohms across the 5V supply is not normal.

Do you still measure 30 ohms with the PCB off the drive?

Do you still measure 30 ohms if you remove the R0 resistors one at a time?

What resistance do you measure between ground and each of Vcore and Vio?

_________________
A backup a day keeps DR away.

Yes, 30 ohm with the PCB off the drive.

Where is R0?

Resistance between Vcore and Vio (and ground) are in the range indicated on the discussion (regular values).

R0 in my diagram refers to the two zero-ohm resistors. The 5V supply appears to diverge at that point.

_________________
A backup a day keeps DR away.

The component i have removed is on the right near fuse. I have lost it. Is it a capacitor?

It appears to be a capacitor. The top end connects to 5V, while the bottom end probably goes to ground. You could confirm that with your meter.

_________________
A backup a day keeps DR away.

Yes a point versus 5v (r0) and a point versus ground. Buy between this point i mesured 33 ohm.

Maybe i burned controller with the shunt on fuse?